Ensemble experiments are performed with five coupled atmosphere–ocean models to investigate the
potential for initial-value climate forecasts on interannual to decadal time scales. Experiments are started
from similar model-generated initial states, and common diagnostics of predictability are used. We find that
variations in the ocean meridional overturning circulation (MOC) are potentially predictable on interannual
to decadal time scales, a more consistent picture of the surface temperature impact of decadal variations in
the MOC is now apparent, and variations of surface air temperatures in the North Atlantic Ocean are also
potentially predictable on interannual to decadal time scales, albeit with potential skill levels that are less
than those seen for MOC variations. This intercomparison represents a step forward in assessing the
robustness of model estimates of potential skill and is a prerequisite for the development of any operational
forecasting system.